Samba notes

Some notes about debugging Samba, mainly because of a problem I encountered for which I found it very difficult to find solutions on the web.

Contents:

Contents

Some useful Samba commands
Mysterious disappearing shares
References

1. Some useful Samba commands

These commands run on a Linux system, and can be used to probe a running Samba server on the same system (or elsewhere as appropriate). They assume Samba client and server are installed.

testparm - check smb.conf file, and lists deviations from default configuration
smbclient -U <name> -L localhost - test connection to server on local machine (requests password for user <name>)
smbclient -d 3 -U <name> -L localhost - as above, but with debugging information
smbtree -U <name> - displayt tree of shares by server on local machine (requests password for user <name>)
smbstatus - displays information about Samba server status

2. Mysterious disappearing shares

(This is also reported at: https://www.scientificlinux.org/bug.feature/bugs/19/pcng_issue_view)

The other day (16 November) my Scientific Linux 4.0 server did a YUM auto-update of Samba from 3.0.10 to 3.0.25b. About the same time, my main share and printing stopped working, which have previously been working faultlessly for about a couple of years. I also lost my printing service.

I dug about on the web, and found some issues relating to Samba 3.0.25 and MSDFS; I've: (a) added

```
msdfs root = Yes 
msdfs proxy = no
```

to my smb.conf, and (b) rebooted by Windows XP client system (repeatedly!) with no change in symptoms.

If I try to mount using NET USE, I see this error:

C:\Documents and Settings\Graham>net use J: \\luggage\files 
System error 67 has occurred.
The network name cannot be found.

(and see a similar problem, with even less useful diagnostic, if I try to connect drive via Windows explorer.)

But, interestingly, my server home directory (per smb.conf [homes]) connects OK:

C:\Documents and Settings\Graham>net use I: 
Local name        I:
Remote name       \\luggage\graham
Resource type     Disk
Status            OK
# Opens           1
# Connections     1
The command completed successfully.

I've also checked modified the services enabled in my XP system, per http://helpdesk.ugent.be/netdisk/en/bestand_mount.php?id=1. Similar problems have been noted on at least two other workstations (XP and Win2K), but those have not been investigated as fully.

Running testparm, I get:

[root@luggage mnt]# testparm 
Load smb config files from /etc/samba/smb.conf
Processing section "[homes]"
Processing section "[printers]"
Processing section "[files]"
Processing section "[dvd]"
Loaded services file OK.
Server role: ROLE_STANDALONE
Press enter to see a dump of your service definitions
[global]
        workgroup = NINEBYNINE
        server string = Luggage on SL-4.0
        interfaces = eth1, lo
        guest account = guest
        log file = /var/log/samba/smbd.log
        max log size = 100
        server signing = auto
        socket options = TCP_NODELAY SO_SNDBUF=8192 SO_RCVBUF=8192
        printcap name = /etc/printcap
        os level = 64
        preferred master = Yes
        local master = No
        domain master = Yes
        wins support = Yes
        ldap ssl = no
        remote announce = 193.123.216.127
        remote browse sync = 193.123.216.127
        idmap uid = 16777216-33554431
        idmap gid = 16777216-33554431
        hosts allow = 193.123.216.64/255.255.255.192
        printing = cups
        cups options = raw
        print command =
        lpq command = %p
        lprm command =
        case sensitive = No
        msdfs root = Yes
        msdfs proxy = no
[homes]
        comment = Home directories
        path = %H
        valid users = %S
        read only = No
        create mask = 0750
        browseable = No
[printers]
        comment = All Printers
        path = /var/spool/samba
        guest ok = Yes
        printable = Yes
        printer name = iconograph
        use client driver = Yes
        browseable = No
[files]
        comment = Main served file area
        path = /raid/file
        read only = No
        create mask = 0774
[dvd]
        comment = DVD on Linux server
        path = /dvd
        guest ok = Yes
[root@luggage mnt]#

There's no useful information in smbd.log

Smbstatus indicates no obvious problem:

[root@luggage ~]# smbstatus 
Samba version 3.0.25b-1.el4.2

PID     Username      Group         Machine
-------------------------------------------------------------------
 4425   graham        graham        conina       (193.123.216.87)
 4421   mandy         mandy         rincewind    (193.123.216.80)

Service      pid     machine       Connected at
-------------------------------------------------------
graham       4425   conina        Sun Nov 18 16:04:03 2007
mandy        4421   rincewind     Sun Nov 18 16:03:08 2007

Locked files:
Pid          Uid        DenyMode   Access      R/W        Oplock SharePath   Name   Time
--------------------------------------------------------------------------------------------------
4425         500        DENY_NONE  0x100001    RDONLY     NONE   /home/graham   .   Sun Nov 18 16:09:33 2007
4425         500        DENY_NONE  0x100001    RDONLY     NONE   /home/graham   .   Sun Nov 18 16:09:33 2007
4421         501        DENY_NONE  0x100001    RDONLY     NONE   /home/mandy    .   Sun Nov 18 16:04:09 2007
4421         501        DENY_NONE  0x100001    RDONLY     NONE   /home/mandy    .   Sun Nov 18 16:04:09 2007

The problem was also present when trying to connect from the same system, using smbclient:

[root@luggage ~]# smbclient -U graham -L localhost 
Password:
Domain=[LUGGAGE] OS=[Unix] Server=[Samba 3.0.25b-1.el4.2]
tree connect failed: NT_STATUS_BAD_NETWORK_NAME
[root@luggage ~]#

I eventually got my system working again, though I'm not sure it's a fix to the problem as originally reported. The clue was here: https://bugs.launchpad.net/ubuntu/+source/samba/+bug/95460. The presence of msdfs proxy in smb.conf was the culprit, and when this was removed my shares started working again.

The testparm output now looks like this:

[root@luggage ~]# testparm 
Load smb config files from /etc/samba/smb.conf
Processing section "[homes]"
Processing section "[printers]"
Processing section "[files]"
Processing section "[dvd]"
Loaded services file OK.
Server role: ROLE_STANDALONE
Press enter to see a dump of your service definitions

[global]
        workgroup = NINEBYNINE
        server string = Luggage on SL-4.0
        interfaces = eth1, lo
        password server = None
        guest account = guest
        username map = /etc/samba/smbusers
        log file = /var/log/samba/smbd.log
        max log size = 100
        socket options = TCP_NODELAY SO_SNDBUF=8192 SO_RCVBUF=8192
        printcap name = /etc/printcap
        os level = 64
        preferred master = Yes
        domain master = Yes
        wins support = Yes
        ldap ssl = no
        remote announce = 193.123.216.127
        remote browse sync = 193.123.216.127
        idmap uid = 16777216-33554431
        idmap gid = 16777216-33554431
        guest ok = Yes
        hosts allow = 193.123.216.64/255.255.255.192
        printing = cups
        cups options = raw
        print command = 
        lpq command = %p
        lprm command = 
        case sensitive = No
        msdfs root = Yes

[homes]
        comment = Home directories
        path = %H
        valid users = %S
        read only = No
        create mask = 0750
        browseable = No

[printers]
        comment = All Printers
        path = /var/spool/samba
        printable = Yes
        printer name = iconograph
        use client driver = Yes
        browseable = No

[files]
        comment = Main shared file area
        path = /raid/file
        read only = No
        create mask = 0774

[dvd]
        comment = DVD on Linux server
        path = /dvd

3. References

-- GrahamKlyne 2007-11-21 22:18:53